[Solved] Given two strings needle and haystack, return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.

Machine Learning Projects

Table of Contents

Question

Given two strings needle and haystack, return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.

Example 1:

Input: haystack = "sadbutsad", needle = "sad"
Output: 0
Explanation: "sad" occurs at index 0 and 6.
The first occurrence is at index 0, so we return 0.

Example 2:

Input: haystack = "leetcode", needle = "leeto"
Output: -1
Explanation: "leeto" did not occur in "leetcode", so we return -1.

Constraints:

  • 1 <= haystack.length, needle.length <= 104
  • haystack and needle consist of only lowercase English characters.

Python Solution

class Solution:
    def strStr(self, haystack: str, needle: str) -> int:
        if needle=="":
            return 0
        else:
            for i in range(len(haystack)):
                if haystack[i]==needle[0]:
                    if haystack[i:i+len(needle)]==needle:
                        return i
            
            return -1

Leave a Comment

Your email address will not be published.